android - 无法链接 OpenCV Android 示例中的 native 库

Question

我有 OpenCV 代码 (c++)，我想在 Android 中使用它。为此，我必须使用 Android NDK .我下载了OpenCV package for Android development (版本 2.4.0)并执行该手册中的所有步骤。基本样本(仅限 Java API)运行没有问题。示例 #3 (教程 3(高级)- 添加 native OpenCV) 从 ndk-builder 正确构建。但是当我试图从 eclipse 在设备上运行/调试它时总是出现异常:

Exception Ljava/lang/UnsatisfiedLinkError; thrown while initializing Lorg/opencv/samples/tutorial3/Sample3View;

在这一行中:

System.loadLibrary("native_sample");

这是完整的 logcat 日志:

05-31 23:41:45.976: W/ActivityThread(9708): Application org.opencv.samples.tutorial3 is waiting for the debugger on port 8100...
05-31 23:41:45.983: I/System.out(9708): Sending WAIT chunk
05-31 23:41:45.983: I/dalvikvm(9708): Debugger is active
05-31 23:41:46.179: I/System.out(9708): Debugger has connected
05-31 23:41:46.179: I/System.out(9708): waiting for debugger to settle...
05-31 23:41:46.382: I/System.out(9708): waiting for debugger to settle...
05-31 23:41:46.585: I/System.out(9708): waiting for debugger to settle...
05-31 23:41:46.788: I/System.out(9708): waiting for debugger to settle...
05-31 23:41:46.983: I/System.out(9708): waiting for debugger to settle...
05-31 23:41:47.186: I/System.out(9708): waiting for debugger to settle...
05-31 23:41:47.389: I/System.out(9708): waiting for debugger to settle...
05-31 23:41:47.585: I/System.out(9708): waiting for debugger to settle...
05-31 23:41:47.788: I/System.out(9708): debugger has settled (1463)
05-31 23:41:47.819: D/szipinf(9708): Initializing inflate state
05-31 23:41:47.866: I/Sample::Activity(9708): Instantiated new class org.opencv.samples.tutorial3.Sample3Native
05-31 23:41:48.909: D/dalvikvm(9708): threadid=1: still suspended after undo (sc=1 dc=1)
05-31 23:41:51.770: I/Sample::Activity(9708): onCreate
05-31 23:41:59.283: W/dalvikvm(9708): Exception Ljava/lang/UnsatisfiedLinkError; thrown while initializing Lorg/opencv/samples/tutorial3/Sample3View;
05-31 23:42:01.965: D/AndroidRuntime(9708): Shutting down VM
05-31 23:42:01.965: W/dalvikvm(9708): threadid=1: thread exiting with uncaught exception (group=0x40015560)
05-31 23:42:01.999: E/AndroidRuntime(9708): FATAL EXCEPTION: main
05-31 23:42:01.999: E/AndroidRuntime(9708): java.lang.ExceptionInInitializerError
05-31 23:42:01.999: E/AndroidRuntime(9708):     at org.opencv.samples.tutorial3.Sample3Native.onCreate(Sample3Native.java:21)
05-31 23:42:01.999: E/AndroidRuntime(9708):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
05-31 23:42:01.999: E/AndroidRuntime(9708):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1722)
05-31 23:42:01.999: E/AndroidRuntime(9708):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1784)
05-31 23:42:01.999: E/AndroidRuntime(9708):     at android.app.ActivityThread.access$1500(ActivityThread.java:123)
05-31 23:42:01.999: E/AndroidRuntime(9708):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:939)
05-31 23:42:01.999: E/AndroidRuntime(9708):     at android.os.Handler.dispatchMessage(Handler.java:99)
05-31 23:42:01.999: E/AndroidRuntime(9708):     at android.os.Looper.loop(Looper.java:130)
05-31 23:42:01.999: E/AndroidRuntime(9708):     at android.app.ActivityThread.main(ActivityThread.java:3835)
05-31 23:42:01.999: E/AndroidRuntime(9708):     at java.lang.reflect.Method.invokeNative(Native Method)
05-31 23:42:01.999: E/AndroidRuntime(9708):     at java.lang.reflect.Method.invoke(Method.java:507)
05-31 23:42:01.999: E/AndroidRuntime(9708):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:864)
05-31 23:42:01.999: E/AndroidRuntime(9708):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:622)
05-31 23:42:01.999: E/AndroidRuntime(9708):     at dalvik.system.NativeStart.main(Native Method)
05-31 23:42:01.999: E/AndroidRuntime(9708): Caused by: java.lang.UnsatisfiedLinkError: Couldn't load native_sample: findLibrary returned null
05-31 23:42:01.999: E/AndroidRuntime(9708):     at java.lang.Runtime.loadLibrary(Runtime.java:429)
05-31 23:42:01.999: E/AndroidRuntime(9708):     at java.lang.System.loadLibrary(System.java:554)
05-31 23:42:01.999: E/AndroidRuntime(9708):     at org.opencv.samples.tutorial3.Sample3View.<clinit>(Sample3View.java:48)
05-31 23:42:01.999: E/AndroidRuntime(9708):     ... 14 more

我找到了相同问题的解决方案，但没有一个对我有帮助:

1. Native OpenCV Samples for Android throws UnsatisfiedLinkError
2. java.lang.UnsatisfiedLinkError: Couldn't load opencv_java: findLibrary returned null
3. Major OpenCV-Android for Windows Installing and Running Issues (没有回答)

此外，我还在不同的设备和 Android API 版本上对其进行了测试。

我的系统配置:

astor@astor-K42Jv:~$ uname -a
Linux astor-K42Jv 3.2.0-24-generic-pae #39-Ubuntu SMP Mon May 21 18:54:21 UTC 2012 i686 i686 i386 GNU/Linux

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我已经尝试了 4 个晚上来解决这个问题(这是我的空闲时间 :))，但没有成功。我的论文真的需要这个，所以任何帮助将不胜感激。

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更新:我已经在 Windows 7 (64) 上测试了这个示例，但结果是一样的。

这似乎是 OpenCV 的错误。

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更新:构建日志:

astor@astor-K42Jv:/opt/eclipse-android/workspace/OpenCV-2.4.0-samples/tutorial-3-native$ ndk-build 
Install        : libnative_camera_r2.2.0.so => libs/armeabi-v7a/libnative_camera_r2.2.0.so
Install        : libnative_camera_r2.3.3.so => libs/armeabi-v7a/libnative_camera_r2.3.3.so
Install        : libnative_camera_r3.0.1.so => libs/armeabi-v7a/libnative_camera_r3.0.1.so
Install        : libnative_camera_r4.0.0.so => libs/armeabi-v7a/libnative_camera_r4.0.0.so
Install        : libnative_camera_r4.0.3.so => libs/armeabi-v7a/libnative_camera_r4.0.3.so
Install        : libnative_sample.so => libs/armeabi-v7a/libnative_sample.so

Answer 1

哇哦!

最后我自己找到了解决这个问题的方法!

我决定调试行:

System.loadLibrary("native_sample");

为此，我从 Android-SDK 下载了 android 源代码，然后将源文件夹 (/opt/android-sdk-linux/sources/android-15) 附加到我的项目。之后我发现错误是:

Cannot load library: link_image[1936]:    37 could not load needed library 'libopencv_java.so' for 'libhello-jni.so' (load_library[1091]: Library 'libopencv_java.so' not found)

实际上这个库不在 lib 目录中。我不知道为什么 ndk-build 忽略了它。所以我决定手动复制和加载它。为此，我从 /opt/OpenCV-2.4.0/libs/armeabi-v7a 复制了 libopencv_java.so 并编辑了 java 代码:

static {
    System.loadLibrary("opencv_java"); //load opencv_java lib
    System.loadLibrary("native_sample");
}

其实类似的问题是:

1. Can not load Opencv libraries in necessitas
2. Android OpenCV: cannot dlopen camera wrapper library

从第二个解决方案中，我发现我可以使用 dlopen 加载库, 但我还没有尝试过。

所以我将编写简单的 bash 脚本来为自己完成(只需复制)。

感谢大家。